The long-term objective of this research project is to study the normal development and subsequent activity of sodium channels found in young spiral ganglion cells within the mammalian auditory system. This has not been reported in the literature. To achieve this goal a descriptive research design will be used to study the developmental characteristics of postnatal rat (P3-P8) spiral ganglion cells using the whole-cell voltage-gated patch-clamp technique. After the properties of the young spiral ganglion cell have been described, an experimental research design will be employed to investigate the neurotoxic effects of lead on the sodium current. By studying this specific neural channel found within the cytoplasmic structure of the spiral ganglion cell, we can begin to describe the ways in which these cells respond to sound and code the descriptive cues associated with sound. By doing this, a better understanding of the function of the spiral ganglion cell as well as the complete developmental characteristics of this cell will be known. That is, the knowledge of anatomical demarcations coupled with the underlying neural cytoplasmic mechanisms necessary to code acoustic stimuli. Once the normal neural mechanisms of sodium channels have been described, the imposition of unwanted neurotoxicants, such as lead upon the function of sodium channels and thus cell activity can be determined. Although other neural structures within the nerve cell must be studied before conclusions can be drawn about the way in which spiral ganglion cells code auditory cues, it is a beginning towards helping physicians, educators, parents and researchers understand sensorineural hearing losses, auditory processing deficits and a host of other problems present in young children and adults.